<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    	*{
			margin: 0px;
			padding: 0px;
		}
		div{
			width: 300px;
			height: 300px;
			border: 3px solid black;
			margin: 0 auto;
			margin-top: 15%;
		}
</style>
<body>
    <div></div>
    <script>
        // var rge2 = new RegExp('abc');
        // var reg = /^abc/; //^是以什么开头
        // var reg = /abc$/; //$是以什么结尾
        // \w 字母数字下划线 \d = 0-9
        // ^[\u4e00-\u9fa5]{1,5}$ 中文
        // var reg = /^[a-zA-Z]\w{4,19}/;//这个区间任意一个都可以

        var reg = /^1[34578]\d{9}$/;


        var ok = reg.test('13123456789');
        console.log(ok);


    </script>
</body>
</html>